The basic reason behind portraying the following viruses as cartoons was to demonstrate a single action. As research develops on these little hell raisers it bexomes apparent that casting them off as "non-living" or "simple"* is nearly impossible. For example its been found that a virus can replicate utilizing damaged or even dead cells.
SO a humanistic portrayal, adequately portrays them as the withholding, complicated, and needy little things that they are.
*i don't know who i'm quoting either
